Tetra Tech INCA provided aerial target placement and GPS derived horizontal and vertical control in support of a 17 mile section of the Light Rail project from the Downtown Seattle Transit Tunnel to Redmond. Work included setting and recovering over 40 primary control points of the WSDOT GIS network and providing horizontal coordinates and elevations on those points using static GPS methods. Surveyors set 90 aerial target control points which were controlled using Real Time Kinematic GPS methods.

Sound Transit selected INCA to develop design mapping including road cross sections for 21,000 linear feet, utility locates and details within the right of way and private ownership for 12 miles along with obscured area mapping totaling 11,000 linear feet. The mapping width is approximately 100 feet along this 17 mile corridor. This work supplements the aerial mapping in AutoCad 2006. The area was mapped at a scale of 1 inch = 20 feet and 1 foot contour interval.

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